US3754908A - Electrophotographic production of colour photoconductive mosaic material - Google Patents

Electrophotographic production of colour photoconductive mosaic material Download PDF

Info

Publication number
US3754908A
US3754908A US00243731A US3754908DA US3754908A US 3754908 A US3754908 A US 3754908A US 00243731 A US00243731 A US 00243731A US 3754908D A US3754908D A US 3754908DA US 3754908 A US3754908 A US 3754908A
Authority
US
United States
Prior art keywords
screen
light
areas
exposure
lines
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US00243731A
Other languages
English (en)
Inventor
R Hercock
S Scrutton
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Ilford Imaging UK Ltd
Original Assignee
Ilford Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Ilford Ltd filed Critical Ilford Ltd
Application granted granted Critical
Publication of US3754908A publication Critical patent/US3754908A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/02—Charge-receiving layers
    • G03G5/04—Photoconductive layers; Charge-generation layers or charge-transporting layers; Additives therefor; Binders therefor
    • G03G5/09—Sensitisors or activators, e.g. dyestuffs
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G13/00—Electrographic processes using a charge pattern
    • G03G13/01—Electrographic processes using a charge pattern for multicoloured copies
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G5/00—Recording members for original recording by exposure, e.g. to light, to heat, to electrons; Manufacture thereof; Selection of materials therefor
    • G03G5/12—Recording members for multicolour processes

Definitions

  • ABSTRACT A process for the production of colour photoconductive material of the mosaic type, wherein areas of the material are sensitive only to selected regions of the visible spectrum which comprises:
  • This invention to colour electrophotography.
  • Photo-conductive material usually comprises a layer of photo-conductive material coated onto a support base which has been rendered electro-conductive, or a layer of photo-conductive material coated onto a layer of electro-conductive material which is in its turn coated onto a support base.
  • the material is charged electrically, the charged material is then im- 1 age-wise exposed to light and in the areas where the light strikes the charge is dissipated.
  • the image is developed usually by applying to the material a toner which comprises particles which adhere to the photoconductive layer in the areas which are still charged.
  • the surface of the photo-conductor layer comprises a mosaic of areas each of which have been selectively spectrally sensitized to light in one of the three regions of the spectrum 2 red, green and blue.
  • spectrum used herein refers to the visible spectrum unless otherwise identified.
  • photo-conductive material which comprises a photo-conductive layer having on its surface discrete areas each of which have been selectively spectrally sensitized to one of three regions of the spectrum, red, blue and green, there being in each of these areas a chemical substance which is capable of forming a dye image which is complementary in colour to the colour of light absorbed by the area.
  • the material is electrolytically developed to stabilise the image and prevent chemical reaction taking place at a later stage in those areas which have been affected by light.
  • the layer is then chemically developed by a coupling type developer to yield a tricolour dye image.
  • colour photo-conductive material of the mosaic type means photoconductive material which comprises a photoconductive layer which has been spectrally sensitized to more than one region of the spectrum and in such a 5 way that each discrete area of the surface is sensitive to light of only one region of the spectrum.
  • the process employed comprises carrying out the steps a, b, c, followed by one sequence of the steps d, e, f, and g, followed by the steps h, i, and j.
  • the process employed comprises carrying out the steps a, b, 0, followed by two sequences of the steps d, e, f, and g, followed by the steps h, i, and j.
  • each pattern of light employed in each step f must be different and that each dye sensitiser employed in each step g must be different.
  • the two patterns of light to which the photo-conductive material is exposed in a first and in a second exposure are such that the areas which are sensitive to only one of the three regions of the spectrum are equal.
  • the three selected regions of the spectrum are red, blue and green.
  • this mosaic mate- 1 rial if it is required that, for example, more of the photoconductive layer should be red sensitive, then the patterns of light are adjusted so that the red sensitive areas are bigger in area than the other areas.
  • One method of preparing colour photoconductive material of the mosaic type, wherein areas are each sensitive only to one of the three regions of the spectrum according to the present invention is by use of two screens, one of which is a screen which comprises a series of light-opaque lines on a transparent background, the area occupied by the opaque lines occupying preferably a third of the area of the screen and eachopaque line being preferably of the same width.
  • the first exposure to light of a wavelength to which the unsensitised photoconductor is sensitive is carried out using a screen, preferably having light opaque lines thereon of equal width, the area of the light-opaque lines on this screen occupying half the area of the screen.
  • the second exposure is carried out so that the lines on the second screen cross at an angle to the lines on the screen used during the first exposure. In this way equal areas of the surface of the photoconductor can be sensitised to the three main regions of the spectrum.
  • the second line screen has on it lines which are opaque to light of a wavelength to which the unsensitised photoconductor is sensitive but which transmit light of a wavelength to which areas of the photoconductor have been made sensitive in the first sensitising operation are sensitive.
  • the unsensitised photoconductor is sensitive only to light of the ultraviolet region of the spectrum.
  • the screen comprised yellow lines on a clear background and the first sensitisation operation ,had made areas of the material sensitive to red-light, then one white light (containing ultraviolet light) exposure of the material through this screen would discharge both the red sensitive and the unsensitised areas of the material in the region of the material covered by the clear areas of the screen, but only the red sensitive areas in the region of the material covered by the yellow lines of the screen would be discharged.
  • one white light (containing ultraviolet light) exposure of the material through this screen would discharge both the red sensitive and the unsensitised areas of the material in the region of the material covered by the clear areas of the screen, but only the red sensitive areas in the region of the material covered by the yellow lines of the screen would be discharged.
  • the lines on the screen in the second exposure cross the direction of the lines in the first exposure at right angles but it is to be understood that the same result may be obtained by arranging for the second exposure to be at an angle other than at right angles to the lines in the first screen exposure. Also a variation in the line width may be employed to produce unequal total areas in the mosaic. In fact in the second screen exposure the width of the lines on the screens may be chosen to produce any desired result in regard to the mosaic of areas produced.
  • the spacing of the line screens is determined by the resolution required. In general from to 300 lines per inch are required.
  • photoconductive material the photoconductive surface of which comprises a mosaic of areas each of which have been spectrally sensitised to one of four regions of the spectrum.
  • the patterns of light to which the material is exposed in exposure b and the two exposures e are produced by exposing the material in each exposure to light of a wavelength'to which the material is sensitive through a screen which comprises a series of lines which are opaque to light of such wavelength on a light transparent background, the'lines in the second exposure crossing at an angle to the direction of the lines in the first exposure and the lines in the thirdexposure crossing at an angle to the direction of the lines both in the first exposure and in the second exposure.
  • the lines of the screen employed in the said second exposure are at substantially 60 to the direction of the lines of the screen employed in the first exposure, and wherein in the said second exposure the lines of the screen employed in the third exposure are at substantially 60 both to the direction of the lines on the screen employed in the first exposure and to the lines on the screen employed in the second exposure.
  • line screens used in the exposures required in this embodiment of the invention can be transparent background screens having lines thereon which are opaque to all light or as previously described lines which are opaque only to light to which the unsensitised photoconductor is sensitive.
  • the width of the lines on the screens are so chosen that equal areas produced in the final mosaic pattern, for example the first screen has one-fourth of its area opaque, the second one-third and the third onehalf.
  • the photoconductor is a layer of zinc oxide in a binder.
  • zinc oxide organic or inorganic photoconductive substances may be used, e.g., polyvinyl carbazole.
  • a particular useful liquid which may be used to sensitise the areas of the photoconductor to one region of the spectrum is liquid sensitiser for colour sensitising the surface of a charged photoconductor layer which comprises a charged suspension of dye-sensitised photoconductive zinc oxide particles in an insulating carrier liquid.
  • a resin fixing agent for example an alkyd resin
  • a charge controlling agent for example a metal soap as ferric stearate.
  • the colour photoconductive material of the mosaic type is to be used in a process wherein a latent image is produced by an electrolytic process as hereinbefore described there is associated with each sensitiser a colour former which will produce a dye which is complementary in colour to the colour of the light absorbed by the sensitiser.
  • FIGS. l-3 illustrate the production of colour photoconductive material of the mosaic type which comprises three sets of areas, each one of which is sensitive to one region of the spectrum.
  • FIGS. 4-7 illustrate the production of colour photoconductive material of the mosaic type which comprises four sets of areas each one of which is sensitive to one region of the spectrum.
  • FIG. 1 shows photoconductive material after the first stage in the preparation of the mosaic material.
  • FIG. 2 shows the same photoconductive material after the second stage in the preparation of the mosaic material.
  • FIG. 3 shows colour photoconductive material of the mosaic type which has been produced by the three stage process of the present invention.
  • the spectrally unsensitised photoconductive material used was prepared by coating a suspension of photoconductive zinc oxide (12 parts by weight) in a toluene solution of an alkyl resin (1 part) on to a conductive base paper the resin being present as the binder. The paper after drying was charged negatively to an 8KV corona charger.
  • the charged photoconductive material was exposed through a screen (A) for30 seconds at 12 inches from a 48 watt tungsten lamp operating at 2,850K.
  • the screen (A) used was a glass screen, a third of the area of which was covered by opaque black lines equally placed across the screen, there being 300 lines to the inch).
  • the material was then sensitised by dipping it into a sensitising toner for 3 minutes, the composition of the toner being 1.0 g. of Patent Blue V dye-sensitised zinc oxide, 0.025 ferric stearate, 2.0 g. of an alkyd resin and 250 ml. odourless paraffin (1.03 Cps at C, at 166C 50 percent distilled over) as a carrier.
  • the photoconductive material was charged negatively to a 8KV corona charger and exposed l2 inches from a lOO watt tungsten lamp covered by an Ilford 204 red filter (Filter no 204 in Ilford Colour Filters Handbook published by Ilford Limited, England). This exposure discharges the material in the areas which have been sensitised with the Patent Blue V dyed zinc oxide, i.e., the red sensitive areas.
  • Screen (B) consists of transparent glass on which are present parallel opaque lines covering half the area of the screen, there being 300 lines to the inch.
  • the material was then sensitised in a sensitising liquid similar to the liquid used above except that the zinc oxide had been sensitised by the use of Rose Bengal dye.
  • FIG. 2 shows diagrammatically a magnified portion of the photographic material after the completion of this stage.
  • the areas 1 are the unsensitised areas, the areas 2 are the red sensitised areas and the areas 3 are the green sensitised areas.
  • FIG. 3 illustrates diagrammatically a magnified portion of the colour photoconductive material.
  • areas 2 are the red sensitised areas
  • areas 3 are the green sensitised areas
  • areas 4 are the blue sensitised areas.
  • the sets of areas 2, 3 and 4 are substantially equal.
  • Colour photoconductive material of the mosaic type has thus been prepared by an photoconductive process without the need to provide careful registration of the screens used.
  • FIGS. 4 to 7 illustrate one method of producing colour photoconductive material which comprises four sets of areas each set of which is sensitive to one region only of the spectrum.
  • FIG. 4 there is shown a magnified portion of photoconductive material after one screen exposure.
  • the areas 11 are the unsensitised material and the areas 12 are the areas which have been sensitised by the use of sensitiser A.
  • the screen used in the exposure to produce this material comprises a series of lightopaque lines on a transparent background the areas occupied by the opaque lines being a quarter of the area of the screen, each line being of the same width.
  • FIG. 5 the same photoconductive material is shown after a second screen exposure and sensitisation step has taken place.
  • areas 11 indicate the unsensitised material and areas 12 indicate the material which has been sensitised by sensitiser A, areas 13 indicate the material which has been sensitised by sensitiser B.
  • the screen used in the second exposure comprises a series of light-opaque lines on a transparent background with the same number of lines per inch as the first screen.
  • the opaque lines occupy one-third of the area of the screen and again each line is of the same width.
  • the second screen is used at an angle of approximately 60 to the first screen in regard to the lines on each screen.
  • the material after the second exposure and sensitisation step comprises a series of parallelograms as indicated in FIG. 5.
  • One method of ensuring that the final material has four sets of areas, each set being of equal area to the others, is to determine the angle at which the third screen is to be used and also the line spacing on the third screen from the dimensions of these parallelograms. If the long diagonal of the parallelograms is taken as one unit of length then the line spacing of the third screen should be two lines per unit of length.
  • the third screen is used in a direction parallel to the short diagonal of the parallelograms.
  • FIG. 6 shows material after such a third exposure and after sensitisation with a third sensitiser C.
  • unsensitised material is 11
  • the areas sensitised by sensitiser A are 12
  • the areas sensitised by sensitiser B are 13
  • the areas sensitised by sensitiser C are 14.
  • the third screen has the correct spacing and is applied at the correct angle there will be no register problems since whatever the position on the screen relative to the'lines already laid down on the material, after exposure and sensitisation by sensitiser C the areas so sensitised will occupy one half of the area of each parallelogram present on the material and thus one quarter of the total area of the surface.
  • FIG. 7 shows the material of FIGS. 6 after a final charging and sensitising step had taken place.
  • the areas 12 have been sensitised with sensitiser A
  • the areas 13 have been sensitised with sensitiser B
  • the areas 14 have been sensitised with sensitiser C
  • the areas 15 have been sensitised with sensitiser D.
  • photoconductive colour material which has a mosaic of equal sets of areas, each set of which is sensitive to one of the four regions of the spectrum. This material has been produced without any registration problems arising in the application of any of the screens during the requisite exposures.
  • the dye sensitised zinc oxide is ball-milled for 2 hours in the following formulation.
  • the red sensitiser is prepared in an identical manner to the blue sensitiser, except that the dye used is Patent Blue V (CI 42,045).
  • the final formulation for ball-milling is as follows 2 g dye sensitised zinc oxide 2 g soya modified alkyd resin 20 ml odourless paraffin C. sensitisation of Zinc Oxide Paper to produce Photoconductive Material of the Mosaic type.
  • The'unsensitised zinc oxide paper is charged by passing it under a corona wire held at 10KV negative.
  • the same corona wire is used for all charging operations in this example, and normally gives a charge acceptance of 200V.
  • the paper is then exposed through a line screen to a watt tungsten lamp held at a distance of 30 cm inches for 0.25 see. This lamp (with or without coloured filters) is used for all the exposures in the example.
  • the line screen has black lines of half the width of the interspaces and has a spacing of lines/cm. The charge remaining is toned by holding the paper in the blue sensitiser for 2 sec. and drying in a stream of warm air.
  • the paper is recharged, exposed uniformly to cyan light (Ilford filters 303, 805 and 809 in combination) for 0.5 sec. and then exposed to a line screen held at right angles to the direction of the first screen using unfiltered light for 0.25 sec.
  • This screen also has a spacing of 120 lines/cm, but the line width is equal to the interspace.
  • the charge remaining is toned by holding the paper in the green sensitiser for 2 sec. and drying a stream of warm air.
  • Thepaper is again recharged and exposed uniformly to cyan light (Ilford filters 303, 805 and 809 in combination) for 1.5 sec.
  • the charge remaining is toned by holding the paper. in the red sensitiser for 2 sec. and drying in a stream of warm air.
  • a process according to claim 1 for producing mosaic material sensitive to three selected regions of the spectrum which comprises carrying out the steps a, b and c, followed by one sequence of the steps d, e, f and g, followed by the steps h, i and j.
  • a process according to claim 2 which comprises using two patterns of light to which the photoconductive material is exposed in a first exposure b and in a second exposure e which are such that the areas of the final colour photo-conductive material which are sensitive to only one of the three regions of the spectrum are equal.
  • a process according to claim 4 which comprises using in the first screen exposure of stage b, a screen in which the area occupied by the said opaque lines is a third of the area of the screen.
  • a process according to claim 5 which comprises using a screen wherein each opaque line is of the same width.
  • a process according to claim 4 which comprises using in the first screen exposure a screen comprising a, series of lines which are opaque to all light.
  • a process according to claim 4 which comprises using in the second screen exposure of stage f a screen ing a series of lines which are opaque to light of that region of the spectrum to which the unsensitised photoconductor layer is sensitive but which transmit light in that region of the spectrum to which the areas of the photoconductive layer toned in step c are sensitive.
  • a process according to claim 4 which comprises using in the second screen exposure of stage f a screen wherein the lines cross the direction of the lines in the first screen exposure of stage b at right angles.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Color Electrophotography (AREA)
  • Photoreceptors In Electrophotography (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
US00243731A 1969-12-08 1972-04-13 Electrophotographic production of colour photoconductive mosaic material Expired - Lifetime US3754908A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB59824/69A GB1291074A (en) 1969-12-08 1969-12-08 Colour electrophotography

Publications (1)

Publication Number Publication Date
US3754908A true US3754908A (en) 1973-08-28

Family

ID=10484477

Family Applications (1)

Application Number Title Priority Date Filing Date
US00243731A Expired - Lifetime US3754908A (en) 1969-12-08 1972-04-13 Electrophotographic production of colour photoconductive mosaic material

Country Status (9)

Country Link
US (1) US3754908A (fr)
JP (1) JPS4913350B1 (fr)
BE (1) BE760032A (fr)
CA (1) CA943385A (fr)
DE (1) DE2060380A1 (fr)
FR (1) FR2072973A5 (fr)
GB (1) GB1291074A (fr)
NL (1) NL7017843A (fr)
SU (1) SU459903A3 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3910789A (en) * 1972-04-25 1975-10-07 Applied Res Australia Color correction process
US4210710A (en) * 1978-06-26 1980-07-01 A. B. Dick Company Photoconductor of varying light sensitivity from center to edges
US4228231A (en) * 1977-10-31 1980-10-14 Eastman Kodak Company Color electrophotographic process, apparatus and recording element useful therein
US4860619A (en) * 1987-04-22 1989-08-29 Yoshida Kogyo K. K. Elongate article processing apparatus with an improved discharge device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4786939A (en) * 1985-08-23 1988-11-22 Konishiroku Photo Industry Co., Ltd. Image forming apparatus

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3910789A (en) * 1972-04-25 1975-10-07 Applied Res Australia Color correction process
US4228231A (en) * 1977-10-31 1980-10-14 Eastman Kodak Company Color electrophotographic process, apparatus and recording element useful therein
US4210710A (en) * 1978-06-26 1980-07-01 A. B. Dick Company Photoconductor of varying light sensitivity from center to edges
US4860619A (en) * 1987-04-22 1989-08-29 Yoshida Kogyo K. K. Elongate article processing apparatus with an improved discharge device

Also Published As

Publication number Publication date
JPS4913350B1 (fr) 1974-03-30
BE760032A (fr) 1971-05-17
FR2072973A5 (fr) 1971-09-24
SU459903A3 (ru) 1975-02-05
CA943385A (en) 1974-03-12
NL7017843A (fr) 1971-06-10
DE2060380A1 (de) 1971-07-01
GB1291074A (en) 1972-09-27

Similar Documents

Publication Publication Date Title
US3052540A (en) Dye sensitization of electrophotographic materials
US3607258A (en) Electrophotographic plate and process
US3525612A (en) Electrophotographic reproduction process employing a light sensitive material and a photoconductive material
US3212887A (en) Laterally disposed coterminously adjacent multicolor area containing graphic reproduction receptor and electrophotographic process of using same
US2962375A (en) Color xerography
US4504137A (en) Apparatus for color electrophotography
US3451811A (en) Electrophotographic imaging processes using electrically photosensitive photochromic materials
US3316088A (en) Process of electrophotography based on electrophotolytic reactions and element therefor
US3458310A (en) Electrophotographic color printing
US3754908A (en) Electrophotographic production of colour photoconductive mosaic material
US3775106A (en) Electrophotographic process
US4524117A (en) Electrophotographic method for the formation of two-colored images
US3672887A (en) Electrophotographic process for multicolor reproduction
GB2028535A (en) Electrophotographic copying
US3871879A (en) Method of forming colored copied image
US3666365A (en) Electrophotographic process and apparatus involving persistent internal polarization
US3915703A (en) Photoconductive composition and element employing a sensitizer and a light filtering substance
US3748125A (en) Color electrophotography using toners of the repellent type
US4465749A (en) Electrostatic charge differential amplification (CDA) in imaging process
US4308330A (en) Color electrophotographic recording element
US4228231A (en) Color electrophotographic process, apparatus and recording element useful therein
EP0250653B1 (fr) Méthode électrophotographique pour formation d'image inversée ou positive-positive
US3298830A (en) Imagewise sensitization of electro-photographic layers
US3861916A (en) Electrophotographic material, element and method
US3595648A (en) Poly-n-vinyl-3-nitro carbazole photoconductive material